1. Filed of the Invention
The present invention relates to battery-based grid energy storage in a power grid, specifically, relates to battery-based grid energy storage for balancing the load of a power grid.
2. Background of the Related Art
Along with the development of the industry and agriculture as well as the improvement of life quality, the demand for electricity is increasing. Although great investment has been put by the government on thermal power energy storages and hydropower storages, it is still hard to meet the increasing demands of the electric power work load.
The work loads of the power grid vary in different periods of a day. Currently, 6-9 pm in the evening is the peak time for electric power usage. Thus, backup energy storage is needed to support the power grid so as to meet the electric power usage during the peak time. Existing backup energy storages in the power grid mainly comprise coal energy storages, oil energy storages, hydropower storages and pumped energy storages.
Among those energy storages, the energy storages using coal and oil are expensive and need long time to start or stop, and cause severe pollution to the environment. Considering the cost, safety and environment protection, the energy storages using coal or oil are not suitable for high peak time regulation. The hydropower storages have high peak regulation ability but the available resource is limited. As a major type of energy storages for high peak regulation, the usage of the pumped energy storages are limited because it requires large site area, takes long time to build and is restricted by certain geographical conditions. Therefore, novel energy storage is needed nowadays to meet the power consumption needs.